The invention disclosed in this application is an apparatus and method for testing the venting characteristics of canning jar lids. As such, the invention in this application involves a specialized apparatus and method for testing the sealing capabilities of a container.
Until now, there has been no standard method for defining the qualities and characteristics of standard canning jar closures for either consumers or quality control experts. Accordingly, an apparatus and method for measuring the quality of these closures in an economical fashion has been sought, both as an aid to defining acceptable consumer standards for these goods and to aid in defining quality control parameters in their manufacture.
Prior art methods of testing canning jar lids were all virtually non-empirical. The general practice, in the past, to test canning jar lids was to can a sample substance in the normal methods of the art, including whatever heating or cooking was to be done, and then test the jar at the end of the canning process to determine if a satisfactory seal was created. This method creates numerous difficulties. Among the problems involved in this testing technique were the time and expense involved in completing a canning cycle, and the large number of uncontrolled variables in this process. In addition, a method resulting in reproduceable, standard results is desired, as there is no present method of quantitatively measuring and defining the key functional characteristics of canning jar closures. Therefore, the need for a reproduceable standardized test which will quickly and easily determine the venting characteristics of canning jar lids when they go through the canning process, has been evident. While the prior art has disclosed methods of testing metal can tops and other containers, none of these has been suitable for this particular purpose. Here disclosed is a method and apparatus for accomplishing this long felt need, which will improve evaluation and quality control of these products in the industry, and aid in defining the quality of these products for the consumer.
A significant difference between the method disclosed herein and the prior art is the fact that this method yields results which may be used to project closure performance under any combination of product and process variations. Prior art methods yielded results which represented closure performance under one set of product and process variables, and consequently lacked projectability of overall functional perormance. The test method of the preferred embodiment of the invention disclosed herein tests closures which are designed to vent during their intended use. Thus the testing techniques disclosed here allow for testing in a manner which emperically determines overall performance rather than determining performance under a single set of conditions.